Hi Karin,
Yes, Kitty Wallis makes it (see
http://www.dakotapastels.com/pigsfix_wallis.shtml)Actually it is a moist paste, not really wet, and comes in jars.
I have taken a pastel making workshop with Patricia Buck Hamilton. It was great fun, but I don't think it is for everyone. Unless you are doing it with a group, or will be using the pastels often yourself, it is an expensive venture. It is also one of the messiest projects you can imagine!
There are pastellists who absolutely swear by it, and who very much enjoy the process...I just feel that there are companies whose only purpose is to make high quality products and I like that!
As you may know though, I would walk through fire for Kitty's sanded pastel paper. It has revolutionized pastel painting.
Chris